During this global COVID-19 pandemic, there have been countless obstacles to regular training. Now, as we start to get back outside, many athletes face restrictions around covering your face when in public or wearing a mask in situations where social distancing isn’t possible in order to help limit the spread of the virus.
As athletes try to run and bike while wearing masks, questions are arising about what effect this has and if it’s bad or good for your training. Anecdotally, a number of athletes have noticed differences while training in a mask—elevated heart rate, higher core temperature. While there is no statistical analysis on this specifically, there has been research that examines the benefits of restricted airflow training.
Restricted airflow training is a fairly new training method used in both aerobic and HIIT (High Intensity Interval Training) workouts. The proposed benefits of restricting your air flow—ie. your breathing—include hypoxic adaptations similar to altitude training and respiratory muscle training, which have been shown to benefit both aerobic and HIIT training. Airflow restriction is created by wearing a mask that covers both your nose and mouth. The amount of restriction can be adjusted to replicate different altitude elevations in order to enhance respiratory muscle training. Many different training-style masks exist, but one of the more common and most researched is the Elevation Training Mask (ETM).
The proposed benefits of the ETM include increased respiratory compensation threshold (RCT), improved ventilation threshold (VT), improved power output (PO) at ventilation threshold, and an increase in the creation of growth hormone, which helps increase hypertrophy (growth) adaptations within the muscle.
Do these proposed benefits actually pan out?
In a study comparing two groups of healthy individuals with no endurance cycling experience, research was done to test the validity of these claims. Participants were divided into two groups, where one group wore the ETM and the other did not. Participants underwent three HIIT training sessions per week for six weeks that included 10 x 30 seconds at peak power output. Participants wearing the mask showed significant improvements in the previously mentioned areas from pre- to post-training. However, both groups showed improvements in peak power output and VO2 max pre- to post-training—meaning it was the training not the mask.
It is also important to note that oxygen saturation levels recovered faster in the control group over the experimental mask-wearing group. This means that the group not wearing the masks achieved improvements in VO2 max and peak power output, while also showing faster recovery of their oxygen saturation levels.
In another study, researchers analyzed the effect of the ETM mask on aerobic capacity and anaerobic endurance, two physiological systems heavily associated with ventilatory threshold. The researchers concluded that those wearing the ETM mask not only showed no significant differences but that the mask may have inhibited training adaptations from taking place. We could conclude this is due to improper recovery between training sessions as oxygen saturation levels were not able to come back to resting levels.
The conclusion here? From a strictly scientific perspective, it may be more beneficial to a triathlete to not wear a restrictive airflow mask, since they can perform more training sessions with proper recovery. Wearing an ETM mask doesn’t appear to have the proposed benefits.
However, current research involving the ETM lacks robustness due to small population sizes and non-specific participants for the training interventions. Further research is needed on specifically trained athletes and larger groups to see if there is any improvement for well-trained athletes. So far, improvements that have been seen to take place are occurring due to the training itself. The improvements we’ve seen for increased ventilation could also be due to the reduced respiratory rate when wearing a mask simulating altitudes above 9,000 feet. The ETM claims of hematological blood adaptations, like those achieved from living at altitude, have not shown to be statistically significant. We typically need to spend multiple hours per day at altitude for many weeks in order to start to show greater hematological adaptations.
What does this all mean for the masks and neck gaiters most of us are wearing to train during the pandemic?
While the masks most of us are using now are not sealed to simulate any levels of altitude, they do raise some questionable training adaptations. Exercising with a mask can lead could increase training exertion by elevating core temperature and increasing heart rate. This means you may experience some heavier breathing and greater stress on the respiratory muscles. The effects in the long run are likely minimal, and no real physiological adaptations would likely take place, but there is something to be said for the potential psychological benefits of training at an increased perceived exertion. Meaning: If it feels harder now and you train yourself to get used to it, imagine how nice it’ll seem when you don’t have to wear a mask anymore.